MUNICH, Germany -- Iranian Foreign Minister Mohammad Javad Zarif says Iran will continue to cooperate with world powers to negotiate an end to the nuclear crisis.

Speaking at the Munich Security Conference on February 2, Zarif said Iran will go "in good faith" to the next meeting of the six world powers and Tehran on February 18 in Vienna.

"What I can promise is that we will go to those negotiations with the political will and good faith to reach an agreement because it would be foolish for us to only bargain for six months," Zarif said.

"That would be disaster for everybody, to start a process and then abruptly end it within six months."

The six world powers negotiating with Iran are the United States, China, Russia, Britain, France, and Germany.

Iran reached a six-month agreement with them in November 2013 to halt its most sensitive nuclear operations in exchange for limited sanctions relief. The six-month period began in January as the European Union and the United States began the lifting of some sanctions.

But Zarif said the continued enforcement of most international sanctions on Tehran undermined Iranian trust in the ongoing negotiating process, which is supposed to lead to a final settlement of the nuclear crisis.

He also said that the result of the sanctions regime so far had only been to increase Iran's determination not to be denied what he called its right to all aspects of nuclear technology, including uranium enrichment.

"I believe it would be a major mistake for our friends to believe that we are here [negotiating] because sanctions have been effective. Had sanctions been effective, Iran would not have produced, instead of 200 centrifuges that we had when sanctions started, 19,000 centrifuges [today]," he said.

"So, those who push for sanctions can claim victory for having added 18,800 centrifuges to Iranian stocks of centrifuges."

Zarif met earlier on February 2 in Munich with U.S. Secretary of State John Kerry.

A State Department spokesperson said Kerry "made clear that the United States will continue to enforce existing sanctions" on Iran while the nuclear talks continue.

'More Needs To Be Done'

Meanwhile, the director-general of the UN's nuclear watchdog agency, the Vienna-based International Atomic Energy Agency (IAEA), told the conference that he welcomed what he called the "progress" in the nuclear talks so far.

"If we think of the future, two things are very important for the IAEA for verification. We should be able to clarify the issues that may have military implications. It is necessary for us to have access to [Iran's] undeclared facilities and activities if there is any," Yukiya Amano said.

"The current situation is that there has been positive and encouraging movement but much more needs to be done."

Tehran has always insisted that its nuclear program is for peaceful ends only. However, Western powers charge Iran with using its nuclear energy program to conceal an effort to acquire nuclear weapons.

The Munich Security Conference, which concluded on February 2, brought together hundreds of global political leaders and defense officials to discuss crises ranging from Iran's nuclear program to Ukraine to Syria.